Organic Semiconducting Materials for Stable OLEDs
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Solution Overview
Problem
There is a challenge in providing organic electronic devices with electron transport materials and emitter host materials that have a sufficiently low LUMO level for easy doping while maintaining high enough LUMO levels for efficient charge and energy transfer, and achieving high thermal stability and transparency.
Innovation Solution
The development of organic semiconducting materials with specific compounds, such as those described by formulae (I) and (II), which can be used in layered structures for devices like OLEDs and solar cells, offering high thermal stability, dopability, and transparency, and can function as electron transport layers, hole blocking layers, or buffer layers, allowing for high conductivity and charge carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If organic semiconducting materials are designed with low LUMO levels for easy doping, then dopability is improved, but charge and energy transfer efficiency deteriorates due to insufficiently high LUMO levels
Solution Approach 1:
The patent applies parameter changes by precisely tuning the LUMO energy level of organic semiconducting materials to an optimal range. The compounds are designed with LUMO levels between -2.0 eV and -3.5 eV, which balances two opposing requirements: being low enough to accept electrons from dopants (enabling easy doping) while being high enough to maintain efficient charge and energy transfer. This energy level optimization resolves the contradiction by finding the optimal parameter value that satisfies both competing requirements.
2Reliability
If transparent organic semiconducting materials are used in optoelectronic devices, then light absorption is reduced improving device efficiency, but thermal stability deteriorates
Solution Approach 1:
The patent employs composite materials by combining transparent organic semiconducting compounds with specific molecular structures (containing heteroatoms like N, O, S in conjugated systems) that inherently provide both optical transparency and thermal stability. The composite molecular design integrates electron-transporting moieties with thermally stable structural frameworks, achieving a material that simultaneously maintains high transparency for efficient light harvesting and high thermal stability for device reliability under operating conditions.
3Productivity
If high mobility organic materials are used in active channels of OTFTs, then device performance is improved, but the electronic band gap becomes insufficiently wide for transparent circuit applications
Solution Approach 1:
The patent applies local quality by designing organic semiconducting materials with spatially differentiated functional characteristics within the molecular structure. Specific regions of the molecule are optimized for high charge carrier mobility (through conjugated pathways and electron-transporting groups) while other regions maintain wide band gap properties (through saturated linkers or heteroatom-containing rings). This local functional differentiation enables the material to simultaneously deliver high device performance and optical transparency for transparent electronics applications.
Data Source
Figure 1~2
AI summary
The present invention relates to an organic electronic device comprising an organic semiconducting material comprising at least one compound according to the formulae (I) to (II).